Electromagnetic radiation can be produced in a variety of ways. For example, the windings of a transformer, such as is commonly found within a power supply, can set up an electrical field which produces electromagnetic radiation. Other devices, such as relays and other components can also produce electromagnetic radiation. Such sources of electromagnetic radiation are not uncommon within electrical systems.
Unfortunately, many devices, such as semiconductor devices, that may also be present within a given electrical system, tend to be highly susceptible to electromagnetic radiation. In such a case, the condition is generally called electromagnetic interference. The effects of electromagnetic interference must be carefully considered during the design and implementation of a given electrical system. If elements of the electrical system that are sensitive to electromagnetic interference are placed too close to a source of electromagnetic radiation, then they may not function properly. This can reduce the overall reliability of the electrical system, or cause it to not function at all.
Thus, electromagnetic interference susceptible parts are preferably located at some distance from the sources of electromagnetic radiation. Sometimes this is not a difficult design constraint within the, electrical system. However, at other times this design constraint provides a multitude of problems with component placement. At the very least it may require a given electrical system to be larger than is otherwise necessary, just so as to put the electromagnetic radiation susceptible parts at a sufficient distance away from the electromagnetic radiation producing sources.
What is needed, therefore, is a system by which an electromagnetic interference susceptible component, such as an integrated circuit, is shielded from electromagnetic interference.